The monitoring of areas for various purposes, such as traffic control, animal or human intrusion deterrence, and/or surveillance for security or other purposes, has become increasingly important with population increases and the pressures of a more complex society. Such concerns are often apparent to the observer, who may readily note remote camera installations and security guards and personnel in banks, shopping malls and other areas, as well as pneumatic or other traffic monitoring devices on the road. Such devices and services can be relatively costly, particularly in the case of monitoring or security personnel. However, in some situations there have been no suitable alternatives to such personnel due to the relatively high power demands of many security systems, such as floodlighting for camera surveillance, etc., as well as the need for human observation.
Additionally, it is well known that an intruder (particularly an animal) may often be frightened away by sudden sounds or noises, and in fact this technique has been used with some success with both human intruders and also in areas such as airports and agricultural areas to keep birds and other animals clear of the area. However, these devices generally operate on a timed basis, whether they are needed at the moment or not. Such systems are wasteful of power and distracting, to say the least, to those working in the vicinity if they are not deactivated.
The need arises for a tracking system which is capable of operating upon demand, i.e., when an intruder or intruders approach the area covered by the system. The system should require relatively low power in normal use, as the additional power required for lights, audio devices, cameras, etc. need only be supplied when required by the primary sensing means. The primary sensing means should be of a passive nature, which renders such sensing means more difficult to detect, as well as further reducing power demands. Moreover, the system should be relatively inexpensive to manufacture and operate in comparison to other systems developed.